Create login / signup page

[MarshallAsch]

The login form should allow a user to sign in using a partner account (we do not want to maintain our own authentication database.

Inital partners should include:

• University of Guelph saml / oauth (this will require collaboration with CCS, @judiMc and probably @MarshallAsch
• github login

Look at passport.js and what they require to be added to the frontend to support this.